Managed Investment Entities (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013 collateralizedloanobligations	Dec. 31, 2012
Managed Investment Entities (Textual) [Abstract]
Percentage of investment of most subordinate debt tranche, Minimum	7.50%
Percentage of investment of most subordinate debt tranche, Maximum	51.20%
Number of collateralized loan obligation entities	9
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments	$ 10	$ 29
Difference between aggregate unpaid principal balance and fair value of CLOs' debt	94	123
Carrying amount of CLO loans in default	4	5
Aggregate unpaid principal balance of CLO loans in default	10	12
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	338	257
Aggregate fair value of investment in collateralized loan obligations, most subordinate debt tranches	118
Senior Debt Obligations [Member]
Variable Interest Entity [Line Items]
Purchased CLO senior debt, face amount	70
Purchased CLO senior debt, purchase price	$ 67

Aggregate unpaid principal balance of variable interest entity loans in default.

No definition available.

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- Definition

Carrying amount of variable interest entity loans in default.

+ References

No definition available.

+ Details

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- Definition

Difference between aggregate unpaid principal balance and fair value of variable interest entity debt.

+ References

No definition available.

+ Details

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- Definition

Difference between aggregate unpaid principal balance and fair value of variable interest entity investments.

+ References

No definition available.

+ Details

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- Details

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- Definition

Number of collateralized loan obligation entities.

+ References

No definition available.

+ Details

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- Definition

Maximum percentage of investment of most subordinate debt tranche of variable interest entity.

+ References

No definition available.

+ Details

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- Definition

Minimum percentage of investment of most subordinate debt tranche of variable interest entity.

+ References

No definition available.

+ Details

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- Definition

Purchased CLO senior debt face amount.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Purchased CLO senior debt purchase price.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the most subordinate debt tranches in the Variable Interest Entity (VIE).

+ References

No definition available.

+ Details

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- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 4

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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